Patients are stratified on the basis of CD4 percentage and age. Patients that previously received a primary hepatitis B vaccine (HBV) series receive an HBV immunization at entry. Other vaccinations may be given (based on age and/or CD4 cell measurement, and immunization status) for PCV at entry and 2 months, and measles-mumps-rubella (MMR) vaccine and PPV at 4 months. Some patients may be administered DTaP at a 6-month visit on the basis of age, previous immunization history, and negative tetanus antibody status. Follow-up visits are done at 8, 12, and 24 months. Blood samples are collected at all clinic visits for assessment of HIV RNA, immune responses against pneumococcus, measles, pertussis, and hepatitis B virus, as well as for laboratory evaluations.